Blackstone can’t be used to repair stone tools and weapons using an anvil

The bug

You can use cobblestone to repair stone tools and weapons using an anvil but you can’t do that with blackstone, while you can use blackstone to craft stone tools and weapons.

How to reproduce:

1. Get a damaged stone pickaxe. You can run this command: /give @p stone_pickaxe{Damage:130} 1

2. Get blackstone. 

3. Put them in an anvil. 

What I observed: You can't repair the pickaxe with blackstone, but with cobblestone you can.

What I expected: Blackstone can also be used to repair stone tools and weapons.